This invention relates to an apparatus for controlling the flow of high-pressure liquid in a liquid circuit to a shearer drum which is mounted on a carrying arm wherein the liquid circuit includes a live seal communicating with passageways extending through a shearer drum shaft and acting on valves in the interior of the drum for directing the high-pressure liquid to only those nozzles on the periphery of the drum which are opposite the working face during rotation of the drum.
As disclosed in U.S. Pat. No. 4,212,497, drum shearer loaders for underground mining are provided with nozzles about the periphery of the shearer drum for the delivery of high-pressure liquid to the mine face area. A liquid line extending through the shearer drum shaft and a valve serves to control the discharge of liquid from only those nozzles which are opposite the actual working face. The valve is formed by a recess communicating with the line which extends around the periphery of the drum through an angle corresponding to an actuation zone wherein only those nozzles located therein discharge liquid. The recess is disposed in a component located in the drum hub, for instance, the shaft carrying the drum but not rotatable therewith, or a non-rotating tube disposed centrally inside the drum drive shaft. The recess is masked by means of the hub which extends in a sealed manner around the drum shaft, or by means of the drum shaft which extends in a liquid-tight manner around the tube, both the hub and the drive shaft rotating with the drum. Radial lines extend to the various nozzles or groups of nozzles from the portion of the bore in the hub for the drive shaft which masks the recess.
As disclosed in copending application Serial No. 416,930, assigned to the Assignee of this application, a drum shearer loader for underground mining includes nozzles distributed about the periphery of the shearer drum. The nozzles are controlled so that high-pressure liquid is discharged from only those nozzles which are opposite the working face and communicate with the minerals thereat. The nozzles are controlled by valves communicating with a liquid line extending through the drum shaft. The valves are part of a live seal which rotates with the drum and is disposed inside the drum at the end thereof projecting from a reduction gearing box. The high-pressure liquid is supplied through a stationary drum shaft to control valves which are part of the live seal that rotate with the drum and extend around the drum shaft. The seal is located inside the drum and, therefore, access is difficult. The valves are actuated by a separate liquid circuit. The liquid discharge apparatus disclosed in the aforementioned U.S. Pat. No. 4,212,497 provides that the operative period during which high-pressure liquid is discharged from the nozzles is controlled directly by the drum shaft and the stationary tube in the shaft bore or by the drum shaft and the drum hub therearound.